The uveal effusion syndrome and trans-scleral flow.

Recent studies of the uveal effusion syndrome, a rare condition characterised by idiopathic spontaneous serous detachment of the retina and peripheral choroid, have suggested a primary scleral abnormality as the underlying cause. In particular, abnormal deposition of glycosaminoglycans within the sclera may impair normal trans-scleral flow of fluid and contribute to increased scleral thickness. In four cases of uveal effusion syndrome, we have confirmed the accumulation of glycosaminoglycans in the sclera. Histochemical studies show that most of this material is proteodermatan sulphate with a smaller contribution from proteochondroitin sulphate, while electron microscopy showed an increase in collagen fibril thickness. Secondary changes within the retinal pigment epithelium were also observed, particularly foci of proliferation which corresponded to the characteristic 'leopard-spot' fundal appearances of this disorder. We therefore suggest that the uveal effusion syndrome is due to a primary defect in proteodermatan synthesis and/or degradation by scleral fibroblasts and may represent a form of ocular mucopolysaccharidosis.